178 EARTH FEATURES AND THEIR MEANING 



the immature stages, and with full maturity the lines of beauty 

 alone are characteristic. As this critical stage is passed irregu- 

 larity of feature and ever more flattened curves are found to cor- 

 respond to the decline of the river's vital energies. There are 

 thus marks of senility in the work of rivers (Fig. 187). 



READING REFERENCES FOR CHAPTERS XII AND XIII 



General : 

 SIR JOHN PLAYFAIR. Illustrations of the Huttonian Theory of the Earth. 



Edinburgh, 1802, pp. 350-371. 

 J. W. POWELL. Exploration of the Colorado River of the West and its 



Tributaries. Washington, 1875, pp. 149-214. 



G. K. GILBERT. Report on the Geology of the Henry Mountains. Wash- 

 ington, 1877, pp. 99-150. (A classic upon the work of rivers.) 

 C. E. BUTTON. Tertiary History of the Grand Canon District (with 



atlas), MOD. 2, U. S. Geol. Surv., 1882, pp. 264. 

 W. M. DAVIS. The Rivers and Valleys of Pennsylvania, Nat. Geogr. Mag. 



vol. 1, 1889, pp. 203-219 ; The Triassic Formation of Connecticut, 



18th Ann. Rept. U. S. Geol. Surv., Pt. ii, 1898, pp. 144-153. 

 SIR A. GEIKIE. The Scenery of Scotland. London, 1901, pp. 1-12. 

 I. C. RUSSELL. Rivers of North America. Putnam. New York, 1898, 



pp. 327. 

 M. R. CAMPBELL. Drainage Modifications and their Interpretation, 



Jour. Geol., vol. 4, 1896, pp. 567-581, 657-678. 

 HENRY GANNETT. Physiographic Types, U. S. Geol. Surv., Topographic 



Atlas, Folios 1-2, 1896, 1900. 

 W. M. DAVIS. The Geographical Cycle, Geogr. Jour., vol. 14, 1899, 



pp. 481-504. 



The flood plain : - 

 HENRY GANNETT. The Flood of April, 1897, in the Lower Mississippi, 



Scot. Geogr. Mag., vol. 13, 1897, pp. 419-421. 

 W. M. DAVIS. The Development of River Meanders, Geol. Mag., Decade 



iv, vol. 10, 1903, pp. 145-148. 

 W. S. TOWER. The Development of Cut-off Meanders, Bull. Am. Geogr. 



Soc., vol. 36, 1904, pp. 589-599. 



River terraces : 



W. M. DAVIS. The Terraces of the Westfield River, Massachusetts, Am. 

 Jour. Sci., vol. 14, 1902, pp. 77-94, pi. 4 ; River Terraces in New Eng- 

 land, Bull. Mus. Comp. Zool., vol. 38, 1902, pp. 281-346. 



River deltas : 

 G. K. GILBERT. The Topographic Features of Lake Shores, 5th Ann. 



